(a)
(b)
(c)
(d)
Figure 4: (a) DESI-MS spectrum of a Tylenol 3 tablet, giving rise to protonated acetaminophen and codeine. (b) PSI-MS spectrum of Tylenol 3. (c) MS/MS spectrum of protonated acetaminophen. (d) MS/MS spectrum of protonated codeine.